A. Making df cost more to register.
B. making a donor trade section for any game.

1. What purpose would that serve?
2. Again, what purpose would that serve and what would it entail?

Please tak a look at this: http://forums.d2jsp.org/topic.php?t=57896631&f=258

and i would say no.
There is no need it to cost more.
and why trade only with donors?

This would serve no purpose..